The main objective of the Vascular Subcore is to provide the essential clinical and pathologic resources to study the contribution of cerebrovascular disease to dementia. Several pathogenetic mechanisms have been proposed to explain how vascular disease can lead to cognitive impairment, including: acute infarction, chronic ischemia and compromise of the blood-brain barrier. Various forms of cerebrovascular disease are highly prevalent in elderly persons and are often integral components of AD. These categories of patients, however, have traditionally been excluded from ADRC Clinical Cores. The unique mission of this Subcore is to recruit and follow patients with vascular or mixed dementias. The specific aims include: 1) recruitment of well-characterized subjects with ischemic vascular dementia, as well as appropriate controls (e.g. subjects with mixed dementia, AD or who are cognitively normal), 2) longitudinal follow-up of subjects, including enrollment in the Rancho Brain Research autopsy program; 3) post-mortem examination of patients including semiquantitative and quantitative characterization of vascular and degenerative lesions in the brain; and 4) distribution of autopsy tissues to ADRC investigators. The resources of this Subcore will support several other research projects, including a comprehensive investigation of neuronal degeneration in the AD visual system. In years 11 to 15, Rancho Los Amigos Medical Center (RLAMC) has been chosen to support these activities for several reasons. Rancho is the site of one of nine State-supported Alzheimer Disease Diagnostic and Treatment Centers (ADDTC) which provides clinical diagnoses and assessment for a variety of dementia patients (120 new patients per year). Approximately 25% of these new patients have mild to moderate dementia and would be appropriate for clinical studies of vascular dementia and vision. An autopsy program has been in smooth operation at Rancho since 1984 (previously, known as the ADRC Cell Quantimetric Core) and will provide neuropathologic data and tissues for research studies.